The Emerald Green Arborvitae, scientifically known as Thuja occidentalis ‘Smaragd,’ is an exceptionally popular evergreen choice for residential and commercial landscapes. This cultivar is highly valued for its striking, year-round emerald color and its signature narrow, pyramidal growth habit. Its dense foliage and upright form make it a preferred option for establishing a low-maintenance, natural privacy screen or a formal hedge. The name ‘Smaragd’ itself is Danish for “emerald,” referencing the tree’s bright, glossy green color that holds well even through winter.
Understanding the Annual Growth Rate
The Emerald Green Arborvitae is generally categorized as a slow to moderate grower, which contributes to its manageable nature in smaller spaces. Under optimal growing conditions, the tree typically adds about 6 to 12 inches of vertical height per year. Some sources suggest that newly planted trees, once established, may exhibit an initial growth spurt of up to 1 to 2 feet annually before settling into a slower pace. The majority of this growth is upward, as the horizontal expansion is much slower, usually only increasing by 1 to 2 inches annually. This predictable, semi-dwarf growth habit is what allows the tree to maintain its narrow columnar shape without needing constant shearing.
Final Mature Dimensions
Understanding the ultimate size of the Emerald Green Arborvitae is important for proper landscape planning, particularly when planting a dense screen. This cultivar is known for reaching a mature height that typically ranges between 10 and 15 feet. It is considered a medium-sized arborvitae, making it suitable for areas where taller varieties would overwhelm the space. The mature width is significantly more constrained due to its naturally narrow form, generally spreading only 3 to 4 feet. Proper spacing, often recommended at 3 to 4 feet apart for a privacy hedge, is determined by this final width to ensure adequate air circulation and prevent over-crowding.
Environmental Conditions That Impact Growth
The rate and extent of growth are heavily influenced by the environment in which the tree is situated. Sunlight exposure is a major factor, with the best growth and foliage density occurring when the plant receives full sun, defined as at least six hours of direct sunlight daily. While it can tolerate partial shade, too little sun will often result in sparser foliage and a reduced growth rate. The tree performs best in rich, well-drained soil; it is important to avoid locations where water consistently pools, as soggy conditions can lead to root rot. This cultivar is also exceptionally cold-hardy, thriving across a wide range of climates, generally in USDA Hardiness Zones 3 through 7.
Care Practices for Consistent Growth
Consistent and deep watering is especially important during the tree’s first few years to help establish a robust root system. Once established, the tree exhibits moderate drought resistance, but weekly watering during extended dry periods will help maintain the vibrant, dense foliage. Applying a layer of arborist mulch around the base of the tree helps to conserve soil moisture and regulate temperature fluctuations around the roots. While these trees do not have a high nutrient demand, a balanced, slow-release evergreen fertilizer applied in the early spring can support healthy growth, especially if the soil quality is poor. Pruning is rarely necessary to maintain the natural pyramidal shape, but light trimming once a year can encourage thicker, denser foliage.